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  <topic id="topic_fstrm">
    <title>pg_trgm</title>
    <body>
      <p>The <codeph>pg_trgm</codeph> module provides functions and operators for
        determining the similarity of alphanumeric text based on trigram matching.
        The module also provides index operator classes that support fast searching
        for similar strings.</p>
      <p>The Greenplum Database <codeph>pg_trgm</codeph> module is equivalent
        to the PostgreSQL <codeph>pg_trgm</codeph> module. There are no
        Greenplum Database or MPP-specific considerations for the module.</p>
    </body>
    <topic id="topic_reg">
      <title>Installing and Registering the Module</title>
      <body>
        <p>The <codeph>pg_trgm</codeph> module is installed when you install
          Greenplum Database. Before you can use any of the functions defined in the
          module, you must register the <codeph>pg_trgm</codeph> extension in
          each database in which you want to use the functions:</p>
      <codeblock>CREATE EXTENSION pg_trgm;</codeblock>
      <p>Refer to <xref href="../../install_guide/install_modules.html"
            format="html" scope="external">Installing Additional Supplied Modules</xref>
          for more information.</p>
      </body>
    </topic>
    <topic id="topic_info">
      <title>Module Documentation</title>
      <body>
        <p>See <xref href="https://www.postgresql.org/docs/9.4/pgtrgm.html"
          format="html" scope="external">pg_trgm</xref> in the PostgreSQL
          documentation for detailed information about the individual functions in
          this module.</p>
      </body>
    </topic>
  </topic>
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